#AHT: What is peripheral arterial disease (PAD)?

Peripheral arterial disease (PAD), also known as peripheral vascular disease or peripheral artery disease, is plaque buildup in your leg arteries that carry oxygen and nutrient-rich blood from your heart to your arms and legs.

Shaped like hollow tubes, arteries have a smooth lining that prevents blood from clotting and promotes steady blood flow. When you have peripheral artery disease, plaque (made of fat, cholesterol and other substances) that forms gradually inside your artery walls slowly narrows your arteries. This plaque is also known as atherosclerosis.

Many plaque deposits are hard on the outside and soft on the inside. The hard surface can crack or tear, allowing platelets (disc-shaped particles in your blood that help it clot) to come to the area. Blood clots can form around the plaque, making your artery even narrower.

If your arteries become narrowed or blocked with plaque or a blood clot, blood can’t get through to nourish organs and other tissues. This causes damage ― and eventually death (gangrene) ― to the tissues below the blockage. This most often occurs in your toes and feet.

The rate at which PAD progresses varies with each person and depends on many factors, including where in your body the plaque forms and your overall health.

What are the risk factors for peripheral arterial disease?
Smoking is the most important risk factor for PAD. In fact, 80% of people with PAD are people who currently or were former smokers.
Regardless of your sex, you’re at risk of developing peripheral arterial disease when you have one or more of these risk factors:

• Using tobacco products (the most potent risk factor).
• Having diabetes.
• Being age 50 and older.
• Being African-American.
• Having a personal or family history of heart or blood vessel disease.
• Having high blood pressure (hypertension).
• Having high cholesterol (hyperlipidemia).
• Having abdominal obesity.
• Having a blood clotting disorder.
• Having kidney disease (both a risk factor and a consequence of PAD).

Although PAD is a different condition from coronary artery disease, the two are related. People who have one are likely to have the other. The U.S. National Institutes of Health estimates that a person with PAD has a six to seven times higher risk of coronary artery disease, heart attack, stroke or a transient ischemic attack(mini-stroke) than the general population. A person with heart disease has a 1 in 3 chance of having peripheral artery disease in the legs.
Not surprisingly, the two diseases also share some common risk factors. This is because these risk factors cause the same changes in arteries in your arms and legs as they do in your coronary arteries.

As in coronary artery disease, many of these risk factors are out of your control. But, according to researchers, tobacco use is the single most important modifiable (changeable) risk factor for PAD and its complications. Tobacco use increases the risk for PAD by 400% and brings on PAD symptoms almost 10 years earlier. Compared with non-smokers of the same age, smokers with PAD are more likely to die of heart attack or stroke, have poorer results with heart bypass surgery procedures on their legs and are twice as likely to have a limb amputation.

How does this condition affect my body?
The typical symptom of PAD is called “claudication,” a medical term that refers to pain in your leg that comes on with walking or exercise and goes away with rest. The pain occurs because your leg muscles aren’t getting enough oxygen.

The dangers of PAD extend well beyond difficulties in walking, and the consequences can be far worse than missing a shopping trip or golf game. Peripheral artery disease increases the risk of developing a non-healing sore of the legs or feet. In cases of severe PAD, these sores can develop into areas of dead tissue (gangrene) that ultimately make it necessary to amputate your foot or leg.

Because your body’s circulatory system is interconnected, the effects of PAD can extend beyond the affected limb. People with atherosclerosis of their legs commonly have it in other parts of their bodies. People who have peripheral artery disease are at increased risk for having a heart attack, stroke, transient ischemic attack (mini-stroke) or problems with their kidney (renal) arteries.

What are the symptoms of PAD?

Half of the people who have peripheral vascular disease don’t have any symptoms, but pain or discomfort in their legs is a common symptom. You may also feel weak or tired while walking. Affected parts of your leg may include your calves, thighs or buttocks.
PAD can build up over a lifetime, and the symptoms may not become obvious until later in life. For many people, the outward symptoms won’t appear until their artery has narrowed by 60% or more.

Early symptoms
The first noticeable symptom of PAD may be intermittent claudication ― leg discomfort, pain or cramping that:

• Develops with activity.
• Goes away with rest.
• Comes back when you resume activity.

You may notice the pain in your calf, but you may also feel it in your buttocks or thighs. With intermittent claudication, your leg muscles may feel:

• Numb.
• Weak.
• Heavy.
• Tired.

The pain can be severe enough to limit your ability to participate in activities you enjoy, such as golfing or chasing after grandchildren.

Reduced blood flow to your leg muscles causes this type of cyclical pain, which goes away at rest because your muscles need less blood flow at rest.

Advanced symptoms

Symptoms of advanced PAD may include:

• A burning or aching pain in your feet and toes while resting, especially at night while lying flat.
• Cool skin on your feet.
• Redness or other color changes of your skin.
• More frequent infections.
• Toe and foot sores that don’t heal.

Diagnosis
Some of the tests your doctor may rely on to diagnose peripheral artery disease are:

• Physical exam.Your doctor may find signs of PAD during a physical exam, such as a weak or absent pulse below a narrowed area of your artery, whooshing sounds over your arteries that can be heard with a stethoscope, evidence of poor wound healing in the area where your blood flow is restricted, and decreased blood pressure in your affected limb.
• Ankle-brachial index (ABI).This is a common test used to diagnose  It compares the blood pressure in your ankle with the blood pressure in your arm.To get a blood pressure reading, your doctor uses a regular blood pressure cuff and a special ultrasound device to evaluate blood pressure and flow.You may walk on a treadmill and have readings taken before and immediately after exercising to capture the severity of the narrowed arteries during walking.
• Ultrasound. Special ultrasound imaging techniques, such as Doppler ultrasound, can help your doctor evaluate blood flow through your blood vessels and identify blocked or narrowed arteries.
• Angiography. Using a dye injected into your blood vessels, this test allows your doctor to view blood flow through your arteries as it happens. Your doctor can trace the flow of the dye using imaging techniques, such as X-rays, magnetic resonance angiography (MRA) or computerized tomography angiography.Catheter angiography is an invasive procedure that involves guiding a small hollow tube (catheter) through an artery in your groin to the affected area and injecting the dye. This type of angiography allows your doctor to treat a blocked blood vessel at the time of diagnosis. After finding the narrowed area of a blood vessel, your doctor can then widen it by inserting and expanding a tiny balloon or by administering medication that improves blood flow.
• Blood tests.A sample of your blood can be used to measure your cholesterol and triglycerides and to check for diabetes.

Treatment
Treatment for peripheral artery disease has two major goals:

• Manage symptoms, such as leg pain, so that you can resume physical activities
• Stop the progression of atherosclerosis throughout your body to reduce your risk of heart attack and stroke

You may be able to accomplish these goals with lifestyle changes, especially early in the course of peripheral artery disease. If you smoke, quitting is the single most important thing you can do to reduce your risk of complications. Walking or doing other exercise on a regular basis following a schedule, referred to as supervised exercise training, can improve your symptoms dramatically.
If you have signs or symptoms of peripheral artery disease, you likely will need additional medical treatment. Your doctor may prescribe medicine to prevent blood clots, lower blood pressure and cholesterol, and control pain and other symptoms.

Medications

• Cholesterol-lowering medications.You may take a cholesterol-lowering drug called a statin to reduce your risk of heart attack and stroke.

The goal for people who have peripheral artery disease is to reduce low-density lipoprotein (LDL) cholesterol, the “bad” cholesterol, to less than 100 milligrams per deciliter (mg/dL), or 2.6 millimoles per liter (mmol/L). The goal is even lower if you have additional major risk factors for heart attack and stroke, especially diabetes or continued smoking.

• High blood pressure medications.If you also have high blood pressure, your doctor may prescribe medications to lower it.

Your blood pressure treatment goal should be less than 130/80 millimeters of mercury (mm Hg). This is the guideline for anyone with coronary artery disease, diabetes or chronic kidney disease. Achieving 130/80 mm Hg is also the goal for healthy adults age 65 and older and healthy adults younger than age 65 with a 10% or higher risk of developing cardiovascular disease in the next 10 years.

• Medication to control blood sugar.If you have diabetes, controlling your blood sugar levels becomes even more important. Talk with your doctor about your blood sugar goals and the steps you need to take to achieve these goals.
• Medications to prevent blood clots.Because peripheral artery disease is related to reduced blood flow to your limbs, it’s important to improve that flow.

Your doctor may prescribe daily aspirin therapy or another medication, such as clopidogrel (Plavix).

• Symptom-relief medications.The drug cilostazol increases blood flow to the limbs both by keeping the blood thin and by widening the blood vessels. It specifically helps treat leg pain in people who have peripheral artery disease. Common side effects of this medication include headache and diarrhea.

An alternative to cilostazol is pentoxifylline (Pentoxil). Side effects are rare with this medication, but it’s generally doesn’t work as well as cilostazol.

Lifestyle and home remedies
Many people can manage the symptoms of peripheral artery disease and stop the progression of the disease through lifestyle changes, especially quitting smoking. To stabilize or improve PAD:

• Stop smoking. Smoking contributes to constriction and damage of your arteries and is a significant risk factor for the development and worsening of  If you smoke, quitting is the most important thing you can do to reduce your risk of complications.
• Exercise. This is a key component. Success in the treatment of PAD is often measured by how far you can walk without pain. Proper exercise helps condition your muscles to use oxygen more efficiently.Your doctor can help you develop an appropriate exercise plan. He or she may refer you to a claudication exercise rehabilitation program.

• Eat a healthy diet. A heart-healthy diet low in saturated fat can help control your blood pressure and cholesterol levels, and that can lower your risk of atherosclerosis.

If you’re having trouble quitting on your own, ask your doctor about smoking cessation options, including medications to help you quit.

Angioplasty and surgery
In some cases, angioplasty or surgery may be necessary to treat peripheral artery disease that’s causing claudication:

• Angioplasty. In this procedure, a catheter is threaded through a blood vessel to the affected artery. There, a small balloon on the tip of the catheter is inflated to flatten the plaque into the artery wall and reopen the artery while stretching the artery open to increase blood flow.

Your doctor may also insert a mesh tube (stent) in the artery to help keep it open. This is the same procedure doctors use to open heart arteries.

• Bypass surgery.Your doctor may create a path around the blocked artery using either a blood vessel from another part of your body or a synthetic vessel. This technique allows blood to bypass the blocked or narrowed artery.
• Thrombolytic therapy.If you have a blood clot blocking an artery, your doctor may inject a clot-dissolving drug into your artery at the point of the clot to break it up.